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Can I Build a Deck on Top of a Concrete Slab? Archadeck Answers Common Questions About Where Decks Can Be Built

If you're thinking about building a new deck in the coming year, you may be wondering if you have the right location for one. Here are the answers to some common questions about the different places a deck can be built.

Can You Build a Deck on…

…a concrete slab? Yes, in some instances, a deck can be used to enlarge an existing concrete pad. It may be a particularly cost-effective approach to utilize the existing concrete structure rather than removing and replacing it with a new wood structure. A deck can be framed directly onto the concrete slab. However, installing point loads onto the patio, such as columns or posts, would exceed the bearing capacity of the concrete pad. Like many specialized applications, we recommend speaking with one of our designers or a licensed engineer prior to building any structure on an existing concrete pad.

…grass? Yes, a low-to-grade deck can be built over grass. A deck should be built high enough to fit joists under the decking boards and to allow adequate ventilation. Building a deck directly onto grass (or any type of ground) can trap moisture that can damage the supports or the decking, which is why ventilation is key.

…a roof? Yes, it is possible to build a deck on top of a roof in the right circumstances, although this is not a recommended application. The easiest roof style to build upon is generally a flat roof, as long as the house structure can properly support it, and it is designed to adequately account for rainwater, snow, and other outdoor elements. Since a deck is a permanent structure, we generally don't recommend installing them over roofs because it blocks future access if a repair should need to be made.

…over a window well? Typically, no, decks cannot be built over window wells. These areas need to remain uncovered, so they can be used as an exit during emergencies.

…over a septic drain field or septic tank? No, decks should not be built over any part of a septic system. Building codes typically require that structures be at least five feet away from septic tanks or lines.

…over an easement? It may be possible to build a deck in an easement. Easements and setbacks differ by jurisdiction, and some may allow a deck to extend into the setback a specifically allocated amount. Sometimes a special variance can be requested to get permission to build into the easement/setback. Our team can help explore this option if needed for a property.

…around a hot tub? Yes, a deck can be built around a hot tub. However, it is advisable to put the hot tub on top of the deck. Our team is well-versed in building decks with engineered substructures to support the weight of a hot tub. If you prefer to have your hot tub on a patio and build a deck around it – we can consult with you directly to find the best option.

…over concrete steps? Yes, a deck can be built over existing concrete steps provided there is enough clearance above the top step to properly connect the deck to the house. Deck skirting is helpful if a deck is going to be built over a previously existing structure in order to hide it from view.

Please note...

All of the above answers are contingent upon local building codes and your individual property's impervious surface limits. While the general answer may be yes, each property has unique opportunities and limitations, which your Archadeck team can help assess.

Are you curious about when to build a deck? Spring and summer are very popular times, but winter is a great time to build your deck in the Raleigh-Durham area.

If you have questions about deck placement or are ready to begin discussing deck options, give Archadeck of Raleigh-Durham a call today at (919) 973-1523. We look forward to working with you!